Physics:Isotopes of fluorine

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Short description: Nuclides with atomic number of 9 but with different mass numbers

Fluorine (9F) has 18 known isotopes ranging from 13F to 31F (with the exception of 30F) and two isomers (18mF and 26mF). Only fluorine-19 is stable and naturally occurring in more than trace quantities; therefore, fluorine is a monoisotopic and mononuclidic element.

The longest-lived radioisotope is 18F; it has a half-life of 109.734(8) min. All other fluorine isotopes have half-lives of less than a minute, and most of those less than a second. The least stable known isotope is 14F, whose half-life is 500(60) yoctoseconds,[1] corresponding to a resonance width of 910(100) keV.

List of isotopes

Nuclide
[n 1] 		Z N Isotopic mass (u)
[n 2][n 3] 		Half-life
[n 4] 		Decay
mode
[n 5] 		Daughter
isotope
[n 6] 		Spin and
parity
[n 7][n 4] 		Physics:Natural abundance (mole fraction)
Excitation energy Normal proportion Range of variation
13F[2] 9 4 13.045120(540)# p ?[n 8] 12O ? 1/2+#
14F 9 5 14.034320(40) 500(60) ys
[910(100) keV] 		p ?[n 8] 13O ? 2−
15F 9 6 15.017785(15) 1.1(3) zs
[376 keV] 		p 14O 1/2+
16F 9 7 16.011460(6) 21(5) zs
[21.3(5.1) keV] 		p 15O 0−
17F[n 9] 9 8 17.00209524(27) 64.370(27) s β+ 17O 5/2+
18F[n 10] 9 9 18.0009373(5) 109.734(8) min β+ 18O 1+ Trace
18mF 1121.36(15) keV 162(7) ns IT 18F 5+
19F 9 10 18.998403162067(883) Stable 1/2+ 1
20F 9 11 19.99998125(3) 11.0062(80) s β− 20Ne 2+
21F 9 12 20.9999489(19) 4.158(20) s β− 21Ne 5/2+
22F 9 13 22.002999(13) 4.23(4) s β− (> 89%) 22Ne (4+)
β−n (< 11%) 21Ne
23F 9 14 23.003530(40) 2.23(14) s β− (> 86%) 23Ne 5/2+
β−n (< 14%) 22Ne
24F 9 15 24.008100(100) 384(16) ms β− (> 94.1%) 24Ne 3+
β−n (< 5.9%) 23Ne
25F 9 16 25.012170(100) 80(9) ms β− (76.9(4.5)%) 25Ne (5/2+)
β−n (23.1(4.5)%) 24Ne
β−2n ?[n 8] 23Ne ?
26F 9 17 26.020050(110) 8.2(9) ms β− (86.5(4.0)%) 26Ne 1+
β−n (13.5(4.0)%) 25Ne
β−2n ?[n 8] 24Ne ?
26mF 643.4(1) keV 2.2(1) ms IT (82(11)%) 26F (4+)
β−n (12(8)%) 25Ne
β− ?[n 8] 26Ne ?
27F 9 18 27.026980(130) 5.0(2) ms β−n (77(21)%) 26Ne 5/2+#
β− (23(21)%) 27Ne
β−2n ?[n 8] 25Ne ?
28F 9 19 28.035860(130) 46 zs n 27F (4−)
29F 9 20 29.043100(560) 2.5(3) ms β−n (60(40)%) 28Ne (5/2+)
β− (40(40)%) 29Ne
β−2n ?[n 8] 27Ne ?
31F 9 22 31.06020(570)# 2 ms# [> 260 ns] β− ?[n 8] 31Ne ? 5/2+#
β−n ?[n 8] 30Ne ?
β−2n ?[n 8] 29Ne ?
  1. ↑ mF – Excited nuclear isomer.
  2. ↑ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. ↑ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  4. ↑ 4.0 4.1 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  5. ↑ Modes of decay:
    EC: Electron capture
    IT: Isomeric transition
    n: Neutron emission
    p: Proton emission
  6. ↑ Bold symbol as daughter – Daughter product is stable.
  7. ↑ ( ) spin value – Indicates spin with weak assignment arguments.
  8. ↑ 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.
  9. ↑ Intermediate product of various CNO cycles in stellar nucleosynthesis as part of the process producing helium from hydrogen
  10. ↑ Has medicinal uses

Fluorine-18

Main page: Physics:Fluorine-18

Of the unstable nuclides of fluorine, 18F has the longest half-life, 109.734(8) min. It decays to 18O via β+ decay. For this reason 18F is a commercially important source of positrons. Its major value is in the production of the radiopharmaceutical fludeoxyglucose, used in positron emission tomography in medicine.

Fluorine-18 is the lightest unstable nuclide with equal odd numbers of protons and neutrons, having 9 of each. (See also the "magic numbers" discussion of nuclide stability.)[3]

Fluorine-19

Fluorine-19 is the only stable isotope of fluorine. Its abundance is 100%; no other isotopes of fluorine exist in significant quantities. Its binding energy is 147801.3648(38) keV. Fluorine-19 is NMR-active with a spin of 1/2+, so it is used in fluorine-19 NMR spectroscopy.

Fluorine-20

Fluorine-20 is an unstable isotope of fluorine. It has a half-life of 11.0062(80) s and decays via beta decay to the stable nuclide 20Ne. Its specific radioactivity is 1.8693(14)×10+21 Bq/g and has a mean lifetime of 15.879(12) s.

Fluorine-21

Fluorine-21, as with fluorine-20, is also an unstable isotope of fluorine. It has a half-life of 4.158(20) s. It undergoes beta decay as well, decaying to 21Ne, which is a stable nuclide. Its specific activity is 4.781(23)×10+21 Bq/g.

Isomers

Only two nuclear isomers (long-lived excited nuclear states), fluorine-18m and fluorine-26m, have been characterized.[1] The half-life of 18mF before it undergoes isomeric transition is 162(7) nanoseconds.[1] This is less than the decay half-life of any of the fluorine radioisotope nuclear ground states except for mass numbers 14–16, 28, and 31. [4] The half-life of 26mF is 2.2(1) milliseconds; it decays mainly to its ground state of 26F or (rarely, via beta-minus decay) to one of high excited states of 26Ne with delayed neutron emission.[1]

External links

References

  1. ↑ 1.0 1.1 1.2 1.3 Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties". Chinese Physics C 45 (3): 030001. doi:10.1088/1674-1137/abddae. https://www-nds.iaea.org/amdc/ame2020/NUBASE2020.pdf. 
  2. ↑ Charity, R. J. (2 April 2021). "Observation of the Exotic Isotope 13 F Located Four Neutrons beyond the Proton Drip Line". Physical Review Letters 126 (13): 2501. doi:10.1103/PhysRevLett.126.132501. PMID 33861136. Bibcode: 2021PhRvL.126m2501C. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.132501. Retrieved 5 April 2021. 
  3. ↑ National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory. http://www.nndc.bnl.gov/nudat2/. 
  4. ↑ Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties". Chinese Physics C 41 (3): 030001. doi:10.1088/1674-1137/41/3/030001. Bibcode: 2017ChPhC..41c0001A. https://www-nds.iaea.org/amdc/ame2016/NUBASE2016.pdf. 

Sources

  • Chisté, V.; Bé, M. M. (2011). Bé, M. M.. ed. Table de radionucléides (Report). CEA (Commissariat à l'énergie atomique et aux énergies alternatives), LIST, LNE-LNHB (Laboratoire National Henri Becquerel/Commissariat à l'Energie Atomique). 



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